** SEGA GENESIS - MEGA VALKYRIE ** Formerly the 3D engine- now becoming a game ! Since last showing : Back face culling of objects added - increase performance by 15% !! Basically we don't draw what gets overdrawn which saves performance - Some scripting helped to sort models into cullable ones and ones that weren't and also analysed co-planer triangles and reworked those to quads for the engine ( a quad is faster vs 2 triangles ) . Optimised quad drawing ~ 2% gain, saved some resetting of the DDA points amongst shared sections. Optimised joypad reading ~ 0.8% speedup every cycle counts haha. Added dither patterns to the renderer so dithered surfaces can be used - only a slight hit to draw speed. Modified the vblank dma timing to allow XGM2 driver to run at full speed without lagging , so now we can switch from XGM1 to XGM2 and gained 5% cpu performance. Added a basic Enemy - much more complex ones to come , hes using the same movement logic as the player attract mode before. No destruction or collision checking yet . Added player attacks - nothing final but a good start. Reworked the camera to keep a constant background load on here so its indicative of a real stage. Maintaining a solid 20 FPS in this demo. @TonimanGalvez is doing great work on map layout and huds, hes made some very nice internal renders of how the game will look once fully populated. Music is a placeholder for now, kindly provided by @laurent_crouzet so we can model music load in the game. #SGDK #SegaMegadriver #SegaGenesis

** SEGA GENESIS E.B.H update ** Added since last update : Woah .. progress this week is wild !! Blitted Starfield ( makes the most of one layer by compositing stars over each other for added parallax ) . Enemy explosions - debris and particles to come yet. New spread shot firepower and 2 levels of both firepower concentrated and spread - this will be upgraded a lot yet . With further types and animations added. New enemies and new Battleships enter the scenes, the new battle ships are spawn 32 bullets in 4 pulses ( 128 bullets each ) .. so bullet counts a nice and heavy in those scenes. Music added !! SFX to come, using XGM2 driver here for a 1.6% cpu load - thats about my budget for it too in this game haha - every cycle counts when we climb to 350 objects onscreen. Huge thanks to @Luke86McQueen for the amazing OST you are listening too now . @GabrielPyron for the player ship frames, @Carsten1349 artwork for Battleship and Red enemy - I've also done a bit of the art myself which has been a nice change from endless coding. Early days but its shaping up . It seems 3 shooters on the go (Parodius , Lufthoheit , EBH ) might be the right number !! #SGDK #SegaGenesis #SegaMegadrive

** EHB - Sega Genesis Bullet Hell ** Another day , another 20%+ speedup , now maintaining 60 FPS - 99% of the time. During transitions from fixed ( red ) to random ( blue ) trajectories a few frames below 60 FPS but now after the transitions holding 60 fps with some buffer to spare , about 82 % CPU with near 320 sprites onscreen , 360 capable. Sprite pattern updates on the multiplexor at this density are a bit intensive, so couple of minor frames drop as new patterns are cached. I do need to spend some cpu on other things besides bullets so this is a good step and proves I'll will be able to push the sprite counts very high without slowdown. #SGDK #SegaMegaDrive #SegaGenesis

* Sega Megadrive Sprite Boxing * I just love sprite boxes, everything boxed is a sprite in the videos !! Its a very usefull feature some emulators support to check boundaries of sprite / overloading situations / see what is going on in games & dev work. Here I use Exodus emulator ( the only emulator that can show sprite boxes on the Sega MD correctly with multiplexed sprites ) , to show the Parodius warm up level and Lufthoheits Cave Stage & Forest Stage . In Parodius , Every 8 scanlines we have 4 x 8x8 star sprites, using up 4 of the 20 sprites per line Limit we have available - 96 in total , which causes us no issues in the warm up levels . Theres close to 150 sprites in certain places in the warmup level. Lufthoheit uses multiplexed sprites as general objects as well as background objects , and is designed to use up to 240 sprites in the engine. H-int color effects and multiplexing are mixed to get more colors onscreen and more sprites than what is normally possible on the MD. Collision is disabled here so i don't halve the sprites onscreen to maximise the swarm. We have now partially done 4 levels in Lufthoheit but with many projects - progress is slowed. The Sega Genesis is a sprite monster !! #Parodius #Lufthoheit #GameDev #SGDK #SegaGenesis

** Sega Genesis - Mega Parodius Update ** Unfortunately introducing the Warmup pre-amble ( start of the level which starts in space ) into stage 1 really broke things for a while. I've taken the approach that its bascially two stages that are seamed together Warmup + general level and they both use different scrolling techniques / palettes / horizontal interupt (h-int) effects and need to change mid level without issue . Coinciding with that jumping into other coding rabbit holes then coming back rusty into something quite broken wasn't great either . The context change in my head took a while but got there in the end haha. The team have been busy also, @GabrielPyron has been busy working on latter level GFX which he has a substantial amount of the game converted now . He's done a great job on the stars and warmup enemies also ! @VTRCHIPMUSIC is also far ahead of me with some latter level music already completed. Every time a revised song is smaller / better - Mega Parodius will be banging I can assure you. Technical bits added to the engine to support the warm-up stage : A 168 sprite multiplexor ( 96 sprite stars made up of 8 sprites re-used 12 times + 72 general purpose sprites ) implemented for the warm up stage. We wanted a substantial visual upgrade to the warmup level as its very plain on the arcade and this is Mega Parodius afterall so one way to get a lot of depth is to use multiplexed stars that all move at different speeds ( 96 different speeds ) . I have dabled with starfields before on the MD in a small way ;-) so this was second nature. The forground is a starfield itself of smaller stars that a line scrolled ( 32 different speeds ) to give more parallax effect. The line scrolling is changed to tile scrolling later for the main level part. The background is not used for the warmup as its pre-loaded with bits of the catboss and background for when the main level starts. The syringes were quite difficult to get right, basically they are homing missiles so they detect position to player and rotate accordingly however they all squirt which is another sprite attached with offsets that needs animating. Tedious is the word. Still to add red syringes and mulicolored enemies firing back . Had issues with the fading out of warmup / fading in of general level as mulitplexor ( star sprites ) needs disabling - fade out / fade in of Backgrounds to occur then color h-ints enabled at the end of the fade to get more colors onscreen. This sort of stuff needs to be timed well and is generally a little painfull to get right. I don't try to destroy all enemies in the vid to show load testing . Performance is strong as the engine is heavily written in 68k assembly with only the level sheduler in C. I think i will be glad to see the end of the Warmup part of the stage, luckily this can be re-used largely for other stages !! #SGDK #Parodius #SegaMegadrive #SegaGenesis

** Sega Genesis 3D engine update 8.5 ** A smaller update - Scrolling left or right of the sprite based background is implemented along with X camera shifting of the 3d plane. The Exodus emulator has been used with sprite boxing enabled so you can see the background sprites making up the object ( their outlines ) and how they move to tilt the image . The background is made up of 112 sprites (51 are multiplexed in that number as the Genesis is limited to 80 without mulitplexing eg basically re-using sprite hardware as the screen is being drawn ) . In a 6 x 17 sprite grid of 16x32 pixel high sprites. If the tilt affect was not neccessary or only 1/2 the angle of tilt effect was needed, I could get away with 1/2 the number of sprites and just used 32x32 sprites instead. I think the tilt effect adds a bit to movement however. This is very similar to how a Neo Geo would build its backgrounds up - in 16 pixel strips however its sprites are tall as the screen or more but the concept of making backgrounds up in 16 pixel wide strips is similar. The NG uses sprites to build any background layers required. Here on the Genesis the reason is rendering is much faster using both the 3d planes and using a total sprite background for this engine. Initially i had a lot of things breaking when I tried to move the camera in the X dimension much , as i'd optimised the vertex transform path heavily and once beyond a certain camera offset the X value was wrapping around causing a lot of breakage in the rendering. Thankfully solved that issue without marginal impact to cpu . It still needs work , perspectives are a bit wrong etc but it won't be hard to fix. Also found some rendering speeds ups, about 8% by optimising fully onscreen quads and optimising the clearing of the frame buffers more efficiently. @TonimanGalvez has been hard at work on HUD elements and more 3d models so will have something to show for that soon. #SGDK #SegaMegadrive #SegaGenesis

** Sega Genesis 3D Engine Update 8 ** Significant improvements all round as you can see and hear from the last update !! Foremost - A huge thanks to @TonimanGalvez who has joined the project to create a bit of 16bit low poly magic. Toni's an Amiga fan but also crazy about game dev in general, he's worked on GBC, GBA, PC, MD, PSP, C64, CPC, MSX... and others. Gaming titles include War Times, Metal Gear, Rocketman, Tintin & Asterix to name a few. He's provided the great new ship model you see on screen - new striped buildings, all the backgrounds / palettes etc. There's a lot of models he's given me which need to be added, also he will be planning a lot of the level design. Very happy to have him help me turn this into something more than a tech demo as I have my hands tied pushing the MD as far as it can go haha - there is no cpu cycle to be spared. Also many thanks to my good friend @laurent_crouzet for the Music for this showing , I wanted to have the music load occurring so we have a realistic benchmark for performance and he was only too obliging. If you're into MD chiptunes check him out !! Since last update : New player model , substantially more detailed than the Arwing. Last update had a 23 triangle Arwing , this update has a 39 triangle custom model from Toni. We had several to choose from , others will be used for enemies . 3D Buffer size increased 25% to 256x160. This was quite tricky as I'm close to the DMA limit even with an extended vblank . Spent a few days thinking of how to do this as like anything retro every solution has a drawback, finally got a workable solution. It makes a big difference to have a bit more vertical height . Z Rotation added ( the screen tilting left to right ) , small hit to vertex transform on cpu thanks to look up tables doing the heavy lifting, saving 4 multiplies per vertex. Multiple speed ups in rendering code. Onscreen paths with no range checking used until Z is close enough to cause clipping , partial onscreen drawing pathes that need to check boundaries, quad rendering completely rewritten - was very very painfull to get right . I found out the hard way that things are great when they are not rotating in the Z axis haha . Partial buffer draw optimisations - which have helped with the massive dma load , sending up to a 20kb buffer in a single frame needs a lot of optimisation. Min / Max tile lines are analysed and only sent if dirtied , reducing most buffer swaps substantially. Still some issues to sort out , at times you can see the flicker near top of screen when frames are near full height . I need to optimise that a bit. Due to the onscreen buffer system a full Sprite background had to be implemented almost Neo Geo style. This flips the usual MD rendering system on its head as it uses both foreground and background layers for a foreground 3d plane and sprites for the background. This presents a few issues, one is to get a tilt effect on the background by using narrow sprites (16x32) we run out of sprites when trying to cover the screen. Thankfully the MD is not limited to 80 sprites, to fix this a 114 sprite multiplexor is used to draw the background, its completely made up of 16x32 sprites ! Why do things this way ? speed . Its the interleaved foreground/background layers that allow a double buffered ram system writing to write to vram using dma in a completely linear fashion - virtually no tile translation needed. The negative is you have no planes for the background, that's where the sprites come in . Thanks to H40 mode we still have a few sprites we can use for effects in the forground also . Thankfully we can implement a fairly good tilt still for the background using sprites, in future updates this will be able to move horizontally also and a bit of vertical movement. XGM1 music driver in use to simulate music cpu load, XGM2 unfortunately with the massive DMA needed to shift the 3d buffers would slow down at times rendering it unusable, XGM1 plays at full speed - albiet with a bit more of a cpu hit. Together with the sprite multiplexor and the music driver active theres a 10 % hit to cpu so I've had to play around with draw distances / object heights and other optimisations to offset that. Not to mention the larger buffer takes more cpu to fill also. Everything is placeholder so will be changed with proper stage design. We are averaging 20 FPS in the current video, I'll push for more as always !! Progress continues on my other projects , updates soon on those - retirement can't come quick enough . #SGDK #SegaGenesis #SegaMegadrive

What an intro haha - thanks !! I've not had as much time as usual unfortunately for MD dev - busy time at work lately - im sure the other devs are the same as I can't see our hobby getting quiet haha ! Nothing is happening as fast as i want it too , I have a couple of significant updates coming though. Parodius work continues, unfortunately what should have been easy part - has had a few unseen difficulties -its nearly sorted but its been frustrating, this part also has a big upgrade on the standard game visuals. 3d engine , significant work has been done , without saying much i think thjs will be rather unique on the MD and push what's possible to the edge. A lot has been added since last showing and a few surprises im sure. Lufthoheit work continues and we are hoping to finish the dark forest stage latter this year . I talked with the team last week and its a similar story RL getting in the way ( im still the main holdup haha ) !! I see new devs everyday in the sgdk discord so I think its just a step in time where everyone's half baked their next update 😉